Saute mushrooms with half stick of butter in pan until browned, set aside

Slice onions in half, and thinly slice each half into half moons (this may seem like alot but they cook down)

In a bowl, mix beef, garlic, onion powder, salt and pepper together

Using a 1/3 measuring cup, form meat into 8 balls and set aside,(using measuring cup ensures equal sized burgers)

Place 1 "meatball" on tin foil or wax paper place other piece of foil/wax paper on top and using a small plate or pan press burger into thin patty

Continue this with all 8 balls

Take cheese slice and fold it in half and then half again

Place cheese in middle of one patty, and then cover with another patty, like a sandwich

Pick up sandwiched Patties and pinch around edges to seal tightly, to ensure no cheese oozes out during cooking

Cook Patties 6-7 mins per side flipping only once

While burgers are grilling, butter buns and lightly toast

Let burgers rest for 5 to 10 mins after cooking !!!

* Kraft singles work best for cheese it makes the gooey and juiciest burgers :-)

Place burgers on buns, top with onions, mushrooms, and sour cream